The present invention generally relates to toy devices for producing optical illusions such as simulating visual effects, for example, X-ray images, and more particularly to eyeglasses capable of simulating X-ray images.
Eyepieces of the foregoing type have been used as X-ray simulating toys. In one of known constructions the eyepieces include a light strainer to be interspersed between a pair of opaque lenses. In another construction of an X-ray simulating toy, at least one of the lenses made of stressed transparent material is transparent and its plane of stress is disposed in a substantially horizontal relationship with the plane of stress of the other lens to simulate an X-ray image when an object to be viewed is in a vertical position.
It has also been known to use a feather as a light straining member in X-ray simulating toys. A feather can be placed between a pair of transparent layers so that the light is deflected which produces a coherent area of a non-uniform transparency whereby brighter portions are interrupted by narrow darker lines.
Applicant's U.S. Pat. No. 3,711,183 discloses an optical toy device comprising an eyeglass frame with a pair of eyepieces each having a lens opening accommodating a lens. Each lens is made of thermoplastic material such as polystyrene or the like and has a plurality of grooves which extend in a predetermined orientation relative to each other. When an object is viewed through the eyeglasses an X-ray image of the object is simulated. The grooves extend generally in a parallel array and in contiguous relationship. Although grooves in the lenses are formed generally in a mold, a diamond tip tool for accurately forming the grooves in the mold has been typically required, which made manufacturing of such grooves rather expensive.
Accordingly, there has always been need to make the production of such toys less expensive.